RR6 (RR-6; RR 6) is a novel, orally bioactive and selective vanin inhibitor. Oral administration of RR6 in rats completely inhibited plasma vanin activity and caused alterations of plasma lipid concentrations upon fasting, thereby illustrating its potential use in chemical biology research.
Physicochemical Properties
| Molecular Formula | C16H23NO4 |
| Molecular Weight | 293.35812497139 |
| Exact Mass | 293.162 |
| CAS # | 1351758-37-6 |
| PubChem CID | 54754611 |
| Appearance | White to off-white solid powder |
| Density | 1.2±0.1 g/cm3 |
| Boiling Point | 559.5±50.0 °C at 760 mmHg |
| Flash Point | 292.2±30.1 °C |
| Vapour Pressure | 0.0±1.6 mmHg at 25°C |
| Index of Refraction | 1.542 |
| LogP | 0.71 |
| Hydrogen Bond Donor Count | 3 |
| Hydrogen Bond Acceptor Count | 4 |
| Rotatable Bond Count | 8 |
| Heavy Atom Count | 21 |
| Complexity | 348 |
| Defined Atom Stereocenter Count | 1 |
| SMILES | CC(C)(CO)[C@H](C(=O)NCCC(=O)CC1=CC=CC=C1)O |
| InChi Key | PTVUGLNOPRZQEY-AWEZNQCLSA-N |
| InChi Code | InChI=1S/C16H23NO4/c1-16(2,11-18)14(20)15(21)17-9-8-13(19)10-12-6-4-3-5-7-12/h3-7,14,18,20H,8-11H2,1-2H3,(H,17,21)/t14-/m0/s1 |
| Chemical Name | (2R)-2,4-dihydroxy-3,3-dimethyl-N-(3-oxo-4-phenylbutyl)butanamide |
| HS Tariff Code | 2934.99.9001 |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| Targets |
Vanin-1 (VNN1) / Pantetheinase (IC₅₀: 0.54 µM for recombinant human vanin-1; 0.040 µM for human serum pantetheinase; 0.041 µM for fetal bovine serum pantetheinase; 0.087 µM for rat serum pantetheinase). No significant inhibition of human serum biotinidase (IC₅₀ > 200 µM). No inhibition of human cathepsins B, L, or papain at up to 200 µM. [1] |
| ln Vitro |
RR6 is a selective, reversible, and competitive inhibitor of mammalian vanins (pantetheinase). It inhibits recombinant human vanin-1 with an IC₅₀ of 0.54 µM (0.43–0.68 µM, 95% CI). Inhibition potency is higher in serum: IC₅₀ values are 40 nM for human serum, 41 nM for fetal bovine serum, and 87 nM for rat serum. Lineweaver-Burk analysis confirmed competitive inhibition with respect to the substrate AMC-Pan. Gel permeation chromatography with bovine serum pre-incubated with RR6 showed complete recovery of vanin activity after separation, indicating reversible binding. RR6 showed no inhibitory activity against biotinidase (IC₅₀ > 200 µM) or against the cysteine proteases cathepsin B, cathepsin L, and papain at concentrations up to 200 µM. [1] |
| ln Vivo |
After fasting, lumen RR6 totally suppressed venous stent activity and increased venous stent concentration in the Wistar piston (150–200 g). In the middle of the piston, an RR6 adjustment of 3 mg/mL nearly entirely inhibited the intravenous stent [1]. Oral administration of RR6 to rats dose-dependently inhibited plasma vanin activity. A single oral dose of 50 mg/kg resulted in complete inhibition of plasma vanin activity lasting up to 8 hours. When administered in drinking water (3 mg/mL) for 4 days, RR6 caused nearly complete inhibition of plasma vanin activity. In rats fasted for 24 hours after 4 days of RR6 treatment (3 mg/mL in drinking water), plasma free fatty acid (FFA) levels significantly increased, and plasma cholesterol levels significantly decreased compared to control rats. Plasma glucose levels were not altered. [1] |
| Enzyme Assay |
Pantetheinase activity was measured using the fluorogenic substrate pantothenate-7-amino-4-methylcoumarin (AMC-Pan). For inhibition assays, samples (recombinant human vanin-1 or diluted serum) were pre-incubated with inhibitor for 10 minutes before adding AMC-Pan (final concentration 10 µM) in PBS pH 7.4. Reactions were stopped after 10 minutes, diluted, and fluorescence was measured (excitation 360 nm, emission 450 nm). IC₅₀ values were determined from dose-response curves using inhibitor dilutions ranging from 10⁻¹⁰ to 10⁻³ M. To determine the mode of inhibition, reactions were performed with varying substrate concentrations (1–300 µM) in the presence or absence of RR6, and data were analyzed using Lineweaver-Burk plots. For measuring activity in undiluted rat plasma from treated animals, a buffered AMC-Pan solution was dried in wells, plasma was added, and hydrolysis was measured as above. [1] |
| Animal Protocol |
For pharmacodynamic studies, female Wistar rats (200–250 g) received a single oral dose of RR6 dissolved in 10% DMSO in PBS at doses of 2, 10, or 50 mg/kg. Alternatively, RR6 was administered via drinking water at concentrations of 0.3, 1, or 3 mg/mL. Blood samples were collected at various time points, and plasma was prepared by centrifugation for pantetheinase activity measurement. For metabolic studies, male Wistar rats (150–200 g) received RR6 in drinking water (3 mg/mL) for 4 days, followed by a 24-hour fasting period. Blood was collected after fasting, plasma was prepared, and metabolites (free fatty acids, glucose, cholesterol) were analyzed using commercial assay kits. [1] |
| ADME/Pharmacokinetics |
Oral administration of RR6 in rats showed dose-dependent inhibition of plasma vanin activity, indicating systemic exposure and bioavailability. A single oral dose of 50 mg/kg led to prolonged complete inhibition of plasma vanin activity for up to 8 hours. Administration via drinking water (3 mg/mL) achieved nearly complete inhibition of plasma vanin activity, suggesting sustained exposure. |
| Toxicity/Toxicokinetics |
No adverse effects on the animals were noted at any dose given in the study (single oral doses up to 50 mg/kg or administration in drinking water at 3 mg/mL for 4 days). [1] |
| References |
[1]. Discovery of small molecule vanin inhibitors: new tools to study metabolism and disease. ACS Chem Biol. 2013 Mar 15;8(3):530-4. |
| Additional Infomation |
RR6 is a pantetheine analogue designed to act as a reversible, competitive vanin inhibitor. It represents a novel chemical biology tool for studying vanin function in health and disease, particularly in relation to lipid metabolism and PPAR-α signaling. The study suggests that vanin-1, a PPAR-α target, may play a role in nutrient/lipid metabolism during fasting, as indicated by the changes in plasma FFA and cholesterol upon RR6 treatment. The compound shows high selectivity for vanins over related enzymes like biotinidase and common cysteine proteases. [1] |
Solubility Data
| Solubility (In Vitro) | DMSO : ≥ 100 mg/mL (~340.88 mM) |
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 3.25 mg/mL (11.08 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 32.5 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 3.25 mg/mL (11.08 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 32.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 3.25 mg/mL (11.08 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 32.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 3.4088 mL | 17.0439 mL | 34.0878 mL | |
| 5 mM | 0.6818 mL | 3.4088 mL | 6.8176 mL | |
| 10 mM | 0.3409 mL | 1.7044 mL | 3.4088 mL |